K. W. Yu's Home Page

• Education
• Position
• Awards
• Reserach Fields
• Reserach Grants
• Professional Activities
• Book
• Selected Recent Publications
• Address/Telephone no./E-mail

Education

1. BSc, The Chinese University of Hong Kong, 1977
2. MSc, University of California, Los Angeles, 1980
3. PhD, University of California, Los Angeles, 1984

Position

1. 1984, Postdoctoral Research Fellow, University of California, Los Angeles
2. 1984-1985, IBM Research Fellow, Ohio State University
3. 1985-1990, Lecturer, Hong Kong Polytechnic
4. 1987, Visiting Research Scholar, University of California, Los Angeles
5. 1990-1994, Lecturer, The Chinese University of Hong Kong
6. 1994-1997, Associate Professor, The Chinese University of Hong Kong
7. Currently, Professor, Department of Physics, The Chinese University of Hong Kong

Awards

1. Advancement of Science and Technology Award, Ministry of Machinery and Electronics Industry, China (December 1992) on Project "First Principles Studies of Static and Dynamic Properties of Composite Materials"
2. Advancement of Science and Technology Award, Ministry of Machinery Industry, China (December 1998) on Project "Physics of Linear and Nonlinear Composite Materials"
3. JSPS Fellowship for Research in Japan (FY2006), Japan Society for the Promotion of Science (2006) on Project "Theoretical Study of Localized Excitations in Graded Materials: Gradons and Their Properties"

Research Fields

1. Condensed Matter Physics
2. Computational Physics

Research Grants

1. RGC Earmarked Grant (2000-2002): First-Principles Approach to Dynamic Electrorheological Effects in Complex Fluids ; [abstract]
2. RGC Earmarked Grant (2001-2003): First-Principles Approach to Dielectric Behavior of Non-Spherical Cell Suspensions ; [abstract]
3. Direct Grant (2001-2003): Computer Simulations of Electrorheological Fluids in the Dipole-Induced Dipole Model
4. Direct Grant (2002-2004): Field-Induced Structural Transformation of Self-Assembled Colloids
5. RGC Earmarked Grant (2003-2005): Electrokinetic Behavior of Suspensions under AC Applied Fields ; [abstract]
6. RGC Earmarked Grant (2004-2006): First-Principles Approach to Graded-Particle Composites ; [abstract]
7. Direct Grant (2005-2007): Nonlinear Optical Properties of Left-handed Metamaterials with Spatial Gradation and Physical Anisotropy
8. Direct Grant (2006-2007): Charge Relaxation of Rotating Particles in Colloidal Suspensions: A First-Principles Study
9. RGC Earmarked Grant (2006-2008): Nano-Optics in Graded Plasmonic Crystals ; [abstract]

Professional Activities

1. Member, Local Organizing Committee, Hong Kong Workshop on Computational Physics, 1993
2. Member, International Scientific Advisory Committee, The 4th International Conference on Computational Physics, 1997
3. Member, Local Organizing Committee, The Third Meeting of World Wide Chinese Physicists, 2000
4. Adjunct Professor, Suzhou University, Suzhou, China, 2002-2005
5. Advisory Professor, East China Normal University, Shanghai, China, 2003-now
6. Expert Consultant, Hokkaido University, Sapporo, Japan, 2004-now

Book

1. J. P. Huang, K. W. Yu
   "New Nonlinear Optical Materials: Theoretical Research"
   Nova Science Publishers, Inc., New York (2007) ; [Monograph]
   
   We have theoretically exploited some new nonlinear optical materials, e.g., colloidal nanocrystals with strong lattice effects, metallic films with inhomogeneous microstructures adjusted by ion doping or temperature gradient, composites of graded (and/or shape-anisotropic) nanoparticles, etc. The proposed materials are difficult or impossible to achieve with conventional, naturally occurring materials or random composites widely discussed in the literature. This book presents a first-hand review of the latest developments in this field.

Selected Recent Publications

1. J. P. Huang, K. W. Yu
   "Enhanced nonlinear optical responses of materials: Composite effects," Phys. Rep., Vol. 431, 87 (2006)
   
   In this article, we review recent theoretical progress in understanding physical processes of composite effects on enhanced third-order nonlinear optical responses of various kinds of the recently-proposed nonlinear optical materials, namely, colloidal nanocrystals with inhomogeneous metallodielectric particles or a graded-index host, metallic films with inhomogeneous microstructures adjusted by ion doping or temperature gradient, composites with compositional gradation or graded particles, and magneto-controlled ferrofluid-based nonlinear optical materials.
   
   
2. K. P. Yuen, M. F. Law, K. W. Yu, Ping Sheng
   "Optical nonlinearity enhancement via geometric anisotropy," Phys. Rev. E, Vol. 56, R1322 (1997)
   For experimental evidences of this work, see APPLIED PHYSICS LETTERS 88: 111911 (2006) and JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 22: 1949 (2005)
   
   
3. Ying Gu, K. W. Yu, Hong Sun
   "Local field distribution in resonant composites," Phys. Rev. B, Vol. 59, 12847 (1999) ; [e-print]
   
   
4. Jones T. K. Wan, K. W. Yu, G. Q. Gu
   "Dynamic electrorheological effects and interparticle force between a pair of rotating spheres," Phys. Rev. E, Vol. 62, 6846 (2000) ; [e-print]
   A mini review was published in INTERNATIONAL JOURNAL OF MODERN PHYSICS B 19: 1163 (2005); For experimental evidences of this work, see PHYSICAL REVIEW E 72: 041508 (2005)
   
   
5. C. K. Lo, Jones T. K. Wan, K. W. Yu
   "Effects of geometric anisotropy on local field distribution: Ewald-Kornfeld formulation," J. Phys.: Condens. Matter, Vol. 13, 1315 (2001) ; [e-print]
   
   
6. Jun Lei, Jones T. K. Wan, K. W. Yu, Hong Sun
   "First-principle approach to dielectric behavior of nonspherical cell suspensions," Phys. Rev. E, Vol. 64, art. no. 012903 (2001)
   For numerical extraction of spectral representation, see PHYSICAL REVIEW B 71: 012101 (2005)
   
   
7. L. Gao, K. W. Yu, Z. Y. Li, Bambi Hu
   "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E, Vol. 64, art. no. 036615 (2001)
   
   
8. Y. L. Siu, Jones T. K. Wan, K. W. Yu
   "Computer simulations of electrorheological fluids in the dipole-induced dipole model," Phys. Rev. E, Vol. 64, art. no. 051506 (2001) ; [e-print]
   
   
9. J. P. Huang, K. W. Yu, G. Q. Gu
   "Electrorotation of a pair of spherical particles," Phys. Rev. E, Vol. 65, art. no. 021401 (2002) ; [e-print]
   
   
10. Y. Gu, K. W. Yu, Z. R. Yang
    "Statistics of level spacing of geometric resonances in random binary composites," Phys. Rev. E, Vol. 65, art. no. 046129 (2002)
    The numerical data of this work has been used to validate a superstatistics in random matrix theory, PHYSICAL REVIEW E 72: 066114 (2005)
    
    
11. Andrew C. T. Wong, K. W. Yu
    "Heterogeneous aggregation in binary colloidal alloys," Physica A, Vol. 312, 50 (2002) ; [e-print]
    
    
12. J. P. Huang, Mikko Karttunen, K. W. Yu, L. Dong
    "Dielectrophoresis of charged colloidal suspensions," Phys. Rev. E, Vol. 67, art. no. 021403 (2003) ; [e-print]
    
    
13. L. Dong, G. Q. Gu, K. W. Yu
    "First-principles approach to dielectric response of graded spherical particles," Phys. Rev. B, Vol. 67, art. no. 224205 (2003) ; [e-print]
    For alternative theoretical approaches (differential replacement procedure), see PHYSICAL REVIEW B 73: 104208 (2006) and JOURNAL OF APPLIED PHYSICS 100: 034906 (2006); see also COMPOSITES SCIENCE AND TECHNOLOGY 67: 728 (2007)
    
    
14. Y. T. C. Ko, J. P. Huang, K. W. Yu
    "The dielectric behaviour of single-shell spherical cells with a dielectric anisotropy in the shell," J. Phys.: Condens. Matter, Vol. 16, 499 (2004)
    
    
15. J. P. Huang, K. W. Yu
    "Optical nonlinearity enhancement of graded metallic films," Appl. Phys. Lett., Vol. 85, 94 (2004) ; [e-print]
    A review on optics of graded nanofilms was published in PHYSICS REPORTS 452: 33 (2007)
    
    
16. L. Dong, Mikko Karttunen, K. W. Yu
    "Spectral representation of the effective dielectric constant of graded composites," Phys. Rev. E, Vol. 72, art. no. 016613 (2005) ; [e-print]
    
    
17. J. J. Xiao, K. Yakubo, K. W. Yu
    "Harmonic vibrational excitations in graded elastic networks: Transition from phonons to gradons," Phys. Rev. B, Vol. 73, art. no. 054201 (2006) ; [e-print]
    See also PHYSICAL REVIEW B 73: 224201 (2006) and JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76: 024602 (2007) for gradons in higher dimensional elastic networks. Implication of gradons on thermal conduction and rectification in elastic networks with mass gradient was reported in PHYSICAL REVIEW B 76: 020301(R) (2007) or [e-print]
    
    
18. J. J. Xiao, K. W. Yu
    "Giant enhanced optical nonlinearity of colloidal nanocrystals with a graded-index host," Appl. Phys. Lett., Vol. 88, art. no. 071911 (2006) ; [e-print]
    
    
19. W. J. Tian, J. P. Huang, K. W. Yu
    "Dynamic effects on nonlinear alternating current responses in electrorheological fluids," Phys. Rev. E, Vol. 73, art. no. 031408 (2006)
    
    
20. J. J. Xiao, K. Yakubo, K. W. Yu
    "Optical switching in graded plasmonic waveguides," Appl. Phys. Lett., Vol. 88, art. no. 241111 (2006) ; [e-print]
    A variety of plasmonic gradons and their transition in graded plasmonic waveguides were reported in APPLIED PHYSICS LETTERS 89: 221503 (2006) or [e-print].
    
    Total Number of SCI Publications (up to June 2008) = 198
    
    Keywords:
    graded films, nanoparticles, anisotropic, depolarization factor, surface plasmon resonance, spectral density, ferrofluids, dielectric function, metal-dielectric composites, electrorheological fluids, colloidal crystals, graded photonic crystals, graded plasmonic crystals, resonant bands, electric field, optical absorption, angular frequency, gradation profile, nanoshell, four-wave mixing, magnetic field, ferromagnetic, red-shifted